A solid-state image sensor in which a semiconductor is used is mounted on many devices such as a digital camera, a video camera, a monitoring camera, a copying machine, and a fax machine. Recently, a so-called CMOS image sensor manufactured by a complementary metal oxide semiconductor (CMOS) process together with a peripheral circuit is often used as the solid-state image sensor.
There is the CMOS image sensor in which a method of using pixels for detecting a focal point with sensitivities asymmetrical with respect to a light incident angle is adopted as an automatic focusing function of a camera. For example, in Patent Document 1, a photodiode in a pixel is divided into two and one of them with a smaller area is used for detecting a focal point as a method of realizing the pixel for detecting a focal point.
Also, recently, an image sensor in which an organic semiconductor and an inorganic compound semiconductor are used as a photoelectric converting film is developed. This generally has an element structure including the photoelectric converting film and electrodes interposing the same from above and below in which at least one of the upper and lower electrodes is separated for each pixel. Herein also, a method of using the pixel for detecting a focal point is suggested.
In Patent Document 2, an organic photoelectric converting element also having a color filter function arranged with the same optical path length as a silicon photodiode of a certain pixel is divided into two in the pixel and used as a pair, and according to this, light with different phase difference is detected and a focal point may be detected. Patent Document 3 enables focal point detection by using a pair of pixels provided with a light shielding film on a light incident side in an organic photoelectric converting element for detecting phase difference.